使用符号Wh、Re、Gr和Fl分别代表谓词“is white”、“is red”、“is green”和“is a flower”，请用谓词逻辑写下列的句子：
a.Some flowers are white.
b.Some flowers are not red.
c.Not all flowers are red.
d.Some flowers are either red or white.
e.There is not a green flower.
f.No flowers are green.
g.Some flowers are not white.
